Tell me about...
Vitamin K
What is
vitamin K?
Vitamin K is a fat-soluble vitamin stored in the liver and
the body's fat reserves. It is one of two naturally occurring
vitamins in the body and is produced by bacteria that line
the gastrointestinal tract.
Why do
we need it?
Vitamin K's most important role is in making many of the
proteins responsible for blood clotting. It also helps produce
a protein called osteocalcin, which plays a crucial role in
maintaining healthy bones, healing fractures and preventing
osteoporosis. Some studies indicate that it helps in maintaining
strong bones in the elderly.
How much
vitamin K should I take?
According to the National Academy of Sciences, the recommended
daily allowance (RDA) for vitamin K is as follows:
- Adult men: 80 micrograms/day
- Adult women: 65 micrograms/day
- Children aged 7-10: 30 micrograms/day
- Infants: 10 micrograms/day
- Pregnant/lactating women: 65 micrograms/day
What are
some good sources of vitamin K?
Canola oil, soybean oil, and green, leafy vegetables (such
as spinach, broccoli, cabbage and turnip greens) are the best
sources of vitamin K. It can also be found in milk, eggs,
beef liver, bran and citrus fruits.
What can
happen if I don't get enough vitamin K?
Because vitamin K is a naturally occurring substance (it
is produced by bacteria in the intestines and stored in the
liver), deficiency is very uncommon. However, deficiency may
occur in people who have trouble absorbing fats, are on long-term
antibiotic therapy, or take other medications such as warfarin
and phenobarbital. Symptoms of vitamin K deficiency include
easy bruising and ruptured capillaries. A low intake of vitamin
K may also increase the risk of hip fractures in women.
What can
happen if I take too much?
Allergic-type reactions, including skin rashes and itching,
have been reported in individuals taking high doses of vitamin
K. People taking an anticoagulant called coumadin (also known
as warfarin) should not take vitamin K supplements without
first consulting a physician.
Other Resources :
The
More You Know About Vitamins
The
More You Know About Nutrition
References
• Garrison R,
Somer E. The Nutrition Desk Reference. New Canaan,
CN: Keats Publishing, 1995.
• Hendler S. The Doctor's Vitamin and Mineral Encyclopedia.
New York: Simon & Schuster, 1990.
• Janson M. The Vitamin Revolution. Greenville,
NH: Arcadia Press, 1996.
• Murray M. Encyclopedia of Natural Medicine,
2nd ed. Rocklin, CA: Prima Publishing, 1998.
• Murray M. Encyclopedia of Nutritional Supplements.
Rocklin, CA: Prima Publishing, 1996.
• Recommended Dietary Allowances, 10th ed. Washington,
D.C.: National Academy Press, 1989.
|
